1. Field of the Invention
This invention relates to eye treatment procedures and devices and particularly to a technique for destroying lens epithelial cells that remain after portions of the natural lens (cataract) has been removed from an eye. Epithelial cells remaining after the natural lens has been removed need to be eliminated to the maximum extent possible, to prevent formation of secondary cataracts. This invention relates to a novel technique for inducing necrosis of the epithelial cells in the lens capsule and to a specially designed ring implant for use with the method is disclosed herein.
2. Description of Related Art
Currently during cataract surgery, a conventional phacoemulsification instrument is used to apply ultrasonic energy to the lens, which breaks up or emulsifies the cataract. An aspiration passageway carries away the fragmented portions of the cataract and an irrigation passageway provides an irrigating fluid to the interior of the lens capsule to clear out the fragments. This procedure is commonly called “irrigation and aspiration”. In addition to removing the lens it is desirable to remove epithelial cells remaining in the lens capsule prior to insertion of the replacement lens, which remain after irrigation and aspiration.
Currently there are several proposed approaches to destroying or mitigating the growth of epithelial cells after cataract surgery and prior to insertion of a replacement lens. They include the use of chemical compounds injected into the lens capsule to kill the cells, the insertion of a capsular tension ring having an inhibitor compound on its surface or various designs to provide a physical barrier to inhibit proliferation and migration of the lens epithelial cells in the posterior capsule of the eye.